Entertainment content is becoming more and more separated from any sort of physical media on which it may be delivered. Modern consumers of entertainment possess numerous devices capable of playing entertainment content, and content may be delivered to these devices in any number of ways. For example, a user's computer may be capable of playing a movie from a DVD, from a removable medium such as a memory card, from a file stored on the user's hard drive, from a remote source streamed over an Internet connection, or in any number of other ways. Providers of content to consumers hope to receive payment for providing such content, and one way for providers to insure payment is to limit the number of playable copies of a particular item a user may play at any one time, or to otherwise insure that a user may play content only in ways and at times acceptable to the provider.
One way in which providers control a user's playing of content is through the inclusion of digital rights management (DRM) information with the content. A copy of a content item is stored a user's device in such a way that the content item is protected using DRM information, and the DRM information needed to play the device is stored on the device onto which the copy is recorded. This DRM information, which may also be accompanied with control information specifying the conditions under which the content item may be played, is stored in a protected area and used to enable playback of the content. One frequently used mechanism for protection of content is to use or create DRM information that includes an encryption key stored in a protected area of a device inaccessible to a user and to encrypt and decrypt content using the encryption key. In playing or using the content, the encryption key may be used to decrypt content as it is streamed from the device, so that the content needed for playing can be decrypted, but a complete decrypted copy of the content is never present.
Because they frequently own many different devices, users may wish to store content on whatever device they wish, even if they accept the restriction to play the content on only one device at a time, or during an agreed upon period, but if a provider delivers content to multiple devices, each with DRM adapted to the device to which the content is delivered, the provider risks losing control over the content.